Perhaps you should try some spelling variations:
quang luat » quan luan, quang cua, quang tuan
dung quang » dang quang, dung quan, luong quang
hieu soat » hieu suat, hieu luat, kiem soat
hieu hoat » hieu hoa, thien hoat, hieu luat
luat ke » luat ve, luan ket
ke soat » kiem soat
luan » quan, lan

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dung luan van ((hieu soat) OR (hieu hoat)) ) OR ( trinh dung quang luat ke soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh dung luan van ((hieu soat) OR (hieu hoat)) ) or ( trinh dung quang luat ke soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( trinh dung luan van ((hieu soat) OR (hieu hoat)) ) or ( trinh dung quang luat ke soat ))*.